1. Field of the Invention
This present general inventive concept relates to multi-color inkjet ink compositions, and more particularly, to multi-color inkjet ink sets including a first ink composition comprising a first colorant and a heterocyclic amine compound and a second ink composition comprising a second colorant having an acid moiety to prevent color bleeding at an interface between ink compositions having different colors.
2. Description of the Related Art
An inkjet recording apparatus displays an image on a printing medium by ejecting ink droplets through a nozzle. An inkjet ink should have an excellent drying property on the printing medium, it should not cause image bleeding, it should result in a uniform image regardless of a type of the printing medium, it should not cause color bleeding at an interface between different colors when used to print multiple colors, and it should have excellent durability (water resistance, light resistance, and rubbing resistance).
There have been various attempts to provide a multi-color inkjet ink set that satisfies such requirements, particularly that prevent color bleeding.
A method of adding diethylene glycol monobutyl ether to an ink as a penetrant (U.S. Pat. No. 5,156,675), a method of adding an ester or an amide diol to an ink (U.S. Pat. No. 5,160,372), a method of adding diethylene glycol monobutyl ether and Surfynol 465 to an ink (U.S. Pat. No. 5,196,056), and a method of adding glycol monobutyl ether and a water soluble emulsion to an ink (U.S. Pat. No. 6,132,502) were suggested in order to reduce a drying time of an ink and color bleeding by enhancing a speed within which the ink is penetrated to a printing medium.
In addition, a method of using an anionic ink and a cationic ink (U.S. Pat. No. 5,198,023), a method of using an ink set that forms a gel by a reaction of a gel former and a gel initiator (U.S. Pat. No. 5,476,540), a method of adding a reactive species to an ink that forms a polymer on contacting a paper (U.S. Pat. No. 4,694,302), and a method of adding a multivalent metal salt to an acid colorant (U.S. Pat. No. 5,428,383) were suggested in order to prevent color bleeding through a reaction between inks or between an ink and a printing medium.
For a multi-color inkjet ink set including an ink composition having an acid colorant and an ink composition having a multivalent metal salt among the above conventional methods, a stability of the ink set may be lowered over a long period of time, thereby forming a precipitate, and nozzle clogging at a cartridge and erosion of a head material may occur.